1. Field of the Invention
The present invention is broadly concerned with gel-based therapy members and methods of use thereof wherein the gel has outstanding pliability and moisture sorbing properties over a very broad temperature range. More particularly, it is concerned with such therapy members and methods which make use of a gel having a water soluble humectant entrapped within a polymeric matrix, the latter preferably including acrylic acid or acrylamide monomer moieties.
2. Description of the Prior Art
The treatment of many injuries such as sprains, contusions or dislocations where immediate swelling is common typically involves application of cold ice compresses or other materials to slow the flow of blood to the injured site, thus reducing swelling. After the initial trauma and swelling due to the injury have subsided, however, it is often advisable to apply heat to the injured area to promote healing. Here again, a number of expedients have been used in the past for this purpose, including hot towels or heating pads.
It has also been proposed in the past to provide therapeutic wraps or compresses which make use of gel materials. For example, U.S. Pat. No. 4,055,188 describes a therapeutic wrap which includes an elongated, pocketed member having refrigerant gel in the pocket. In use, the gel is refrigerated and placed in the pockets, whereupon the complete device is wrapped about an area to be treated. Similar devices are described in U.S. Pat. Nos. 4,092,982 and 4,243,041.
U.S. Pat. No. 3,780,537 describes a hot and cold compress device which includes an outermost, liquid impervious envelope containing a liquid gel designed to maintain its gel-like consistency over a temperature range of from about 0-212.degree. F.
While the gel-based therapy wraps of the above identified patents have been proposed, they are deficient in a number of respects. For example, it is desirable that a therapy wrap maintain its desirable pliability and other physical properties over as broad a temperature range as possible. This permits stocking of only a single kind of therapy wrap for a given type of injury, which can be used either for heating or cooling therapy. In addition, a desirable gel-based therapy member should be non-flowing, i.e., the gel component should maintain its consistency and self-sustension even if the composite is punctured. In addition, many prior gels are deficient in that they have poor moisture absorption characteristics, or are encased within a material which in effect forms a moisture barrier. Desirably, a gel used in a therapy wrap should be able to absorb and desorb moisture as necessary, in order to maintain a moisture equilibrium at the patient's skin and, in the case of heat therapy, to give a desirable "moist heat" effect.
In addition, a number of gel-based materials have been proposed for use in cushion or pad devices. For example, U.S. Pat. Nos. 3,858,379, 3,308,491, 3,663,973 and 3,548,420 are concerned with various types of pad constructions. Finally, highly successful pad composites commercialized as "Elastogel.TM. Seat Cushions" have been distributed by Southwest Technologies, Inc. of Kansas City, Mo. These pads comprise a layer of soft polymeric gel covered with a four-way stretch, breathable, moisture-pervious fabric. The gel employed in these pad devices (which are used, for example, as wheel chair seat pads) comprises a quantity of glycerin entrapped within an acrylamide polymeric matrix.
It has also been known in the past to provide various types of materials as burn dressings. As is well known, severe burns are excruciatingly painful for a patient, and can present severe and even life threatening problems if the burned skin sloughs off exposing subdermal layers. In the context of a burn treatment device, it would be desirable to provide a dressing or covering which would in effect form a substitute "skin" for the patient. This would require that the dressing "breathe" , or have adequate air permeability characteristics. At the same time, it is desirable that proper moisture conditions be maintained for prompt healing of burned skin; for example, an appropriate dressing should not absorb excessive moisture and thus dry the burned skin, inasmuch as this will inhibit proper healing.
In short, while therapy members such as therapeutic wraps and dressings have been proposed in the past, and in certain instances gel-based formulations have been used, these prior devices and methods of use thereof have presented a number of significant problems.